All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There is no harm on you for performing the Prayer at your workplace, and the Prophet said: “The earth has been made for me (and for my followers) a place for praying on and a thing to perform Tayammum with. Therefore, my followers can pray wherever the time of a prayer is due.” [Al-Bukhari and Muslim]
You are not sinful for not joining the congregational prayer in the mosque, even according to the scholars who are of the view that the congregational prayer is an obligation, because the fear of harm that will result by your leaving work is considered one of the permissible excuses for not going to congregational prayer.
The jurists mentioned a number of excuses by which it is permissible to stay behind from praying in congregation in the mosque, including the fear of harm in a livelihood that he needs.
If you pray in a group, you shall receive the reward of congregational prayer. The Prophet said: “A man's prayer offered with another man is purer than his prayer which he offers alone, and his prayer with two men is purer than his prayer with one man, and if they are more (in number), it is more beloved to Allah Almighty.” [Abu Dawood and an-Nasa-i; and Ibn Hibban graded it as Saheeh (authentic)]
Obtaining the reward of congregational prayer is not specific to the mosque. Rather, wherever a Muslim prays in congregation with others, he will obtain its reward, even if there are several other rewards in the mosque congregation, such as the reward of every step one takes, the reward of waiting for the prayer, the reward of angels asking forgiveness for the person, and other virtues mentioned in the Sunnah. However, the reward of the congregation is attained by those who pray in the mosque and others.
Whoever does not find another person to pray with him in congregation, let him pray alone.
Perhaps Allah may record for him the reward of the congregation, if He knows that the person is keen on praying in congregation. The Sharee’ah has indicated that if the person is prevented from an act of obedience that he used to do regularly because of an excuse, then Allah writes for him its reward.
The Hadith reads: “When a man is ill or on a journey, what he was accustomed to do when staying at home and well will be recorded for him.”
Besides, Anas narrated that the Prophet was in an expedition and said: “Some people have remained behind us in Medeena and we never crossed a mountain path or a valley, but they were with us (i.e. sharing the reward with us), as they have been held back by a (legal) excuse.”
An-Nawawi said in Sharh Saheeh Muslim:
“This Hadeeth indicates the virtue of having the intention to do good and that whoever intended to participate in the expedition, and other acts of worship, but then there was an excuse which prevented him from doing so, he gets the reward of his intention, and that the more he feels remorse for not attending, and wished that he was among the fighters and others, the more his reward will be.” [End of quote]
Ibn Hajar said in Fat-h al-Bari: “This Hadeeth indicates that a person gets with his intention the reward of the doer if there was an excuse that prevented him from doing it.”
Allah Knows best.